Chitosan-based Biohybrid Hydrogels For Tissue Regeneration

The possibility to combine natural and synthetic polymer characteristics is certainly one of the most appealing solutions for the development of functional and bioactive polymers. Simple blends of natural and synthetic polymers, without structural modifications, represent a first step in this direction. A different approach is to covalently link a natural polymer with a synthetic structure via grafting or copolymerization thus obtaining biohybrid (natural plus synthetic) polymers. Among natural polymers, chitosan, a cationic polysaccharide structurally similar to glycosaminoglycans, is reported to possess excellent biological properties such as biodegradability, antibacterial and wound-healing activity, and it is widely studied as a non viral vector for gene delivery. In spite of its fascinating characteristics, only recently the interest of biomedical research focused on this biopolymer as complexation agent, or crosslinked by different agents. However, the critic solubility (only acidic aqueous media) deeply limits its chemical modification, necessary to meet the different structural requirements for different applications. The possibility to obtain of biohybrid polyurethane-chitosan hydrogels was explored. Polyurethane-grafted-chitosan were synthesized by a heterogeneous synthetic method. Chitosan grafted polyethylene oxide and polyethylene adipate polyurethane hydrogels were prepared.